Steam Engine stalls?

[pete_mcfarlane]

Not steam locos, but I was at Crich last week, and what started out as a lovely day turned to rain and greasy rails.

 

It was fun watching the trams making a start from the Terminus, with much wheelslip, grinding to walking pace, and application of sand. One of the crews commented that you'd expect the Sheffield 'Roberts' to cope better with hills, being from Sheffield. So go to Crich on a rainy day and you can see this close up

 

 

[Gilbert]

1 hour ago, Jeremy Cumberland said:

There are a variety of causes. We recently had 35018 British India Line stall at Dalton Bank on the Cumbrian Coast line. Not particularly surprising in the leaf fall season and with the weather at the time - there had been adhesion problems on the Ravenglass and Eskdale Railway earlier that day. As far as I am aware, the locomotive crew acted in the best manner possible and no damage was caused, but the train was stuck there for over two hours awaiting assistance from Carnforth, with service trains being delayed as a result.

 

 

I was on that trip and it was what prompted my original posting. The lack of diesel on the rear was the topic of much discussion at Carlisle among both rail enthusiasts and other passengers such as my other half who was surprised we had no "insurance" for the trip south.

Chris

Edited November 10, 2023 by Gilbert

[DCB]

The classic "Stall" was when a loco was overloaded or not steaming well and came to a halt with regulator wide open and the loco in full gear.  

It should be no surprise to any one that a Merchant Navy or an A2 suffer from slipping, they were plagued by it from new.   Unfortunately after 1923 designers got into a competition to out do each other for powerful locos and Tractive Effort became the bench mark. Collet kicked it off with the Castle having a  greater TE than Gresley's A1.    Gresley responded, he got an A1 up to 36 000lbs but it suffered from slipping and had to be run with partially closed regulator, so settled on a 220lbs psi boiler and smaller cylinders.   The V2 followed suit but, big but, in service they were notably inferior to ex GCR B7 locos, designed for the same duties,  in starting trains on steep grades, despite something like a 33 000 lbs TE against 24 000 ish.   Gresley had to adopt the 2-8-2 layout for his high powered locos for the hilly Aberdeen road.   Probably sadly he used a 50sq ft firebox when 40 would have done, and 220 lbs pressure when 180 would have done., and over stressed the crank axles which broke.   Why didn't Thompson just reduce the Boiler pressure on the P2 (and other Gresleys) to reduce wear?

Anyway when the new P2 gets into service we will see how it copes and maybe for the future perhaps new build sure footed locos should be the goal, a GWR 47XX,  GCR Lord Faringdon, Cardean?
Or maybe a powered coach  like a scaled up Kitmaster, ) Class 73 bogies and power plant in what looks like a GUV, maybe with a water tank as well.

[PhilH]

Locomotives with trailing trucks can be prone to slipping when starting away or accelerating as they tend to 'sit back' so relieving the driving wheels of some adhesive weight, more weight going onto the trailing truck. 

 

The same effect can be observed to a certain degree when driving a car, the front end will lift slightly under acceleration. The extreme example of this effect would be a motorcycle wheelie.

Edited November 10, 2023 by PhilH

[Flying Pig]

On 23/10/2023 at 12:54, Jeremy Cumberland said:

Exactly right. Creep control tries to detect the smallest discrepancy, because this gives the fastest recovery, re-synchronising the speed of the wheels with the speed of the train. 

 

My understanding of Creep Control is that it deliberately operates in the "creep zone" with the wheels slipping, because the coefficient of friction is greatest with a small amount of relative movement between wheel and rail, counter-intuitive as this may be.

[melmerby]

1 hour ago, PhilH said:

Locomotives with trailing trucks can be prone to slipping when starting away or accelerating as they tend to 'sit back' so relieving the driving wheels of some adhesive weight, more weight going onto the trailing truck. 

This is why a GWR castle was more surefooted when starting than many pacifics with a similar load.

Presumably the same will apply to something like a Royal Scot or similar.

[The Stationmaster]

3 hours ago, Jeremy Cumberland said:

There are a variety of causes. We recently had 35018 British India Line stall at Dalton Bank on the Cumbrian Coast line. Not particularly surprising in the leaf fall season and with the weather at the time - there had been adhesion problems on the Ravenglass and Eskdale Railway earlier that day. As far as I am aware, the locomotive crew acted in the best manner possible and no damage was caused, but the train was stuck there for over two hours awaiting assistance from Carnforth, with service trains being delayed as a result.

 

Who is to blame for the delay to other trains? Not the locomotive owners or the train crew, that I can see. Network Rail, perhaps, for not maintaining suitable railhead conditions, but the usual class 156s seemed to manage just fine. The schedulers for allowing such a train to run at dusk in late October, where there is always a risk of dew and leaves creating a horrible slippery coating on the railhead? Quite possibly. Or perhaps it should be the train operator for not attaching the usual diesel on the rear or the line operator (I don't know who is responsible here) for not insisting on it.

 

To my mind, the decision to run such a train at such a time of day/time of year without a second locomotive attached is dubious, but I expect the company most at risk from the decision - Northern Trains - had no say in the matter.

 

Even some of the well-known examples where damage was caused and blaming the driver might seem obvious, I am not entirely sure it is so clear cut. Blue Peter's famous wheelslip came unexpectedly, and if the locomotive primed (always a risk with wheelslip), then it might be very difficult to shut the regulator. Western Champion at North Queensferry seems in large part due to the driver not being familiar enough with the traction to understand what was going on, but who appointed the driver to this duty? Certainly with Western Champion, it is hard to attach any blame to the locomotive owners unless it was they who appointed the driver, so I can't see why it should be their insurers who had to pick up the bill for damage to the track.

I think these two examples point to a particular problem with historic traction on main line trips - as there are no regular workings it will be almost impossible to find a crew who thoroughly know the road and the traction but more importantly know the behaviour of that traction over that particular road.  All of those who do have that knowledge and experience with main line are by now long retired.  Even with some diesels, especially hydraulics, I doubt if there is anybody left in main line railway employment who drove them regularly and definitely nobdy who drive them in any part of .Scotland.

 

However good someone is with a particular loco they are very unlikely to have everyday experience of them over all but a very few routes.  so there is familarity and exerience gap which won't help.  in addition i think some tour organisers are probably too ambitious and that is not helped when their requirements have to be fitted into the everyday working of the railway.  so problems like these will sometimes arise (although they might perhaps be mitigated by more realistic planning?).

[The Stationmaster]

24 minutes ago, Flying Pig said:

 

My understanding of Creep Control is that it deliberately operates in the "creep zone" with the wheels slipping, because the coefficient of friction is greatest with a small amount of relative movement between wheel and rail, counter-intuitive as this may be.

Creep control used in Britain is basically electronically controlled wheel slip.  Plus rail head treatment in the case of the Class 59   -  the only one I have direct experience of riding when the system operates.  In operation on a 59 I reckon it is probably the easiest way for a human being to experience what it would be like riding on an angle grinder -  once material is being applied to the railhead to improve grip.   And in the example I experienced seeing what it did with a 5,100+ ton trailing test load on a 1 in 138 rising gradient was exactly what it says on the tin.  So we happily cleared that route for 5,000 ton trailing loads in normal working with a 59.

[faulcon1]

In the mid 1990's here in NSW Australia we had GM EMD locos enter service of 4,000hp the 90 class and at that time the heaviest diesels in state at 165 tons each that were built in Canada. They were supposed to easily haul the coal trains they were given. But even two of them on 84 wagons had terrible trouble with adhesion with the problems being traced to the radar guided wheel slip control. The Canadians hadn't wired up the latter stages of the wheel slip control thinking we wouldn't need it. But they had no idea just how much the railways intended to get out of the new diesels. The wheel slip control can be heard working by a high pitched ringing sound with the locos down to a crawl on a 1 in 60 grade or steeper. In inclement weather banking engines are still used and usually 81 class which is the father of the class 59. It was the success of the 81 class GM's that was the reason in the mid 1980's that Foster Yeoman (as it was then) bought the class 59's. Now of course 4,000hp diesels here are a dime a dozen and diesels now come with the ability to lower their horsepower depending on how heavy the train is. The NR diesel locos that haul the Ghan and Indian Pacific luxury trains work in pairs and don't need 8,000hp to haul the train even though both trains can load to over 30 coaches. They can increase or decrease the amount of horsepower that is needed. Electric locos hauling passenger trains are a thing of the past here because when the freight operations were privatised the state government not only charged private operators access charges to run trains on the state's rail network but if using electric loco power they also charged for the electricity the locos used. So by using only diesels there was one charge that didn't have to be paid and as for environmental concerns?, what environmental concerns.         

[Michael Hodgson]

It's not just steam engines that can stall with the wheels spinning ...

 

https://www.iricen.gov.in/ModelRoom/H1_Wheel Burnt Rails.html

https://www.thedieselstop.com/media/rail-burn-4.17610/

[roythebus1]

14 hours ago, Michael Hodgson said:

It's not just steam engines that can stall with the wheels spinning ...

 

https://www.iricen.gov.in/ModelRoom/H1_Wheel Burnt Rails.html

https://www.thedieselstop.com/media/rail-burn-4.17610/

They had similar problems at Salisbury when locos were trying to haul the derailed trains out of the tunnel after the collision there a couple of years ago. the trains were wedged in the tunnel! 

[john new]

Recall a class 37 on one of the Weymouth Harbour specials several years back slipping and sending sparks flying off the rails. Generally flat track but twisty and without any regular trains. 

[david.hill64]

On 11/11/2023 at 00:14, Flying Pig said:

 

My understanding of Creep Control is that it deliberately operates in the "creep zone" with the wheels slipping, because the coefficient of friction is greatest with a small amount of relative movement between wheel and rail, counter-intuitive as this may be.

Which is why modern WSP systems try to control wheel speed in braking so that it is almost synchronous.

 

A small amount of slippage has a conditioning effect on the wheel-rail interface, cleaning it and improving adhesion.

 

The downside of small creep values is that the largest tangential stresses in the contact area occur just sub-surface of the interface. This promotes rolling contact fatigue damage, hence we now grind rails to remove the damages surface layer before the cracks can propagate.